John P. Kastelic is a Professor of Theriogenology at the Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada. He received his DVM (with distinction) from the University of Saskatchewan (1982), an MS (1988) and Ph.D. (1990) in reproductive physiology from the University of Wisconsin-Madison, and a Professor of Honoris Causa (2007) from Szent István University (Budapest, Hungary). He was a practicing veterinarian in Alberta (1982–1984) and a research scientist at the Agriculture & Agri-Food Canada Lethbridge Research Centre (1990–2012) before joining the University of Calgary (2012). He is a Diplomate of the American College of Theriogenologists, served on the examination committee (2001–2008), and was designated Theriogenologist of the Year (2009). His research interests are in clinical theriogenology and reproductive biology. He has published widely on ovarian function in cattle, scrotal/testicular thermoregulation, and reproductive development in bulls. He has a special interest in scientific writing. He was co-editor-in-chief of the journal Theriogenology from 2003 to 2010 and is currently co-editor-in-chief of the Canadian Veterinary Journal (since 2021). Furthermore, he has given lectures and workshops on science and science writing on four continents.